Antifoamant composition



2,695,879 Patented Nov. 30, 1954 ANTIFOAMANT COMPOSITION John Adam Jehle, Jr., Media, Pa., assignor to Socony- Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application January 16, 1953, Serial No. 331,735

12 Claims. (Cl. 25246.7)

This invention relates to the reduction of the foaming tendencies of mineral lubricating oils. It is more particularly concerned with providing extreme pressure lubricating oils having little or no tendency to form a stable foam.

As is well known to those familiar with the art, many lubricating oils have marked tendencies to foam while in use. If the foam is of a stable nature, there is a danger that it will eventually displace the lubricating oil in the lubrication system. As a consequence, circulation of sufficient lubricant will be poor, and, more seriously, there will be insuflicient lubricant available to lubricate bearing surfaces, and the like. Foaming is most pronounced in lubricating oils used under extreme pressure conditions, particularly in oils for lubricating hypoid gears in motor vehicles. During operation of such vehicles, the rapid movement of the gears tends to aerate the oil. If a stable foam is formed, insuflicient oil is available to lubricate the gear teeth. Most gear oils, per se, tend to foam. However, the foaming tendencies thereof are often greatly enhanced by the addition of additives for the purpose of increasing film strength, i. e., the extreme pressure additives.

It has now been found that the foaming tendencies of mineral lubricating oils can be sharply reduced, economically and simply. It has now been discovered that the foaming tendencies of mineral lubricating oils can be reduced to a minimum by adding thereto minor amounts of certain monoesters of sorbitol anhydrides, or polyoxyethylene derivatives thereof, and of the reaction product of an alkyl phenol and P205, within a critical range of ratios by weight.

Accordingly, it is a broad object of the present invention to provide non-foaming mineral lubricating oils. Another object is to provide a combination of certain monoesters of sorbitol anhydrides or polyoxyethylene derivatives thereof with the reaction product of an alkyl phenol and P205, in critical ratios, which combination eliminates foaming tendencies of mineral lubricating oils. A further object is to provide a non-foaming mineral lubricating oil containing a minor amount of this critical combination of additives. A specific object is to provide a non-foaming extreme pressure lubricant containing minor amounts of the aforementioned combination of additives. Other objects and advantages of the present invention will become apparent to those skilled in the art, from the following detailed description.

The present invention provides a mineral lubricating oil containing between about 0.1 per cent and about 1.5 per cent, by weight, of an antifoamant composition consisting of between about 2 per cent and about 30 per cent, by weight, of an ester selected from the group consisting of aliphatic monoesters of sorbitol anhydrides and aliphatic monoesters of polyoxyethylene derivatives of sorbitol anhydrides, and between about 98 per cent and about 70 per cent, by weight, of the reaction product formed by reacting about 3 moles of an alkyl phenol having a total of between about 8 carbon atoms and 12 carbon atoms in the alkyl radicals thereof, with about 1 mole of phosphorus pentoxide, at a temperature of between about 75 C. and about 125 C.

In general, any mineral lubricating oil which has foam forming tendencies is improved by the addition of the compositions of this invention. Depending upon the intended application of the lubricant, the viscosity of the oil can vary from about 1 to about 10,000 centistokes at 100 F. The extreme pressure lubricating oils are especially preferred. These oils usually have viscosities logolai tween about 10 and about 1500 centistokes at The ester additives utilizable in the antifoamant compositions of this invention are fatty acid esters of hexitans and hexides obtained by dehydrating sorbitol, and certain polyoxyethylene derivatives thereof. The compounds contemplated are known as Spans and Tweens, which are manufactured by the Atlas Powder Company, Wilmington, Delaware. According to the manufacturers literature, these esters are prepared by first dehydrating sorbitol to produce a mixture of hexitans and hexides having the following formula:

HOCH

O OH OH OH O HO-CH ]CH2 CH1 CHOH OH J 0 This mixture of hixitans and hexides is then esterified by reacting it with one or more moles of a fatty acid to form the Spans. The Tweens are similar thereto except that the unesterified hydroxy groups in the hexitans and hexides have polyoxyethylene chains added thereto. It has been found that only the monoesters of fatty acids having between 12 and 18 carbon atoms are effective. In other words, the diand tri-esters, and even the lower and higher monoesters, are not effective. For purposes of brevity, these esters, throughout the specification and claims, will be referred to as fatty acid monoesters of sorbitol anhydrides and polyoxyethylene derivatives thereof. Non-limited examples of the esters contemplated herein are sorbitol anhydride monolaurate, sorbitol anhydride monomyristate, sorbitol anhydride monopalmitate, sorbitol anhydride monostearate, sorbitol anhydride mono-oleate, sorbitol anhydride monolinoleate, and polyoxyethylene derivatives of the foregoing monoesters. Further data on the monoesters utilizable herein are attainable in a brochure entitled Atlas Surface Active Agents published in 1948 by the manufacturers, supra. Reference should be made thereto, and it is considered to be a part of this specification.

The alkylphenol-P205 reaction products used in the compositions of this invention are the reaction products produced by reacting an alkylphenol with phosphorus pentoxide in a molar proportion of about 3:1, respectively. The phenol reactant can be a monoor a polyalkyl phenol, provided that the total number of carbon atoms in the alkyl radicals is at least 8 and not more than 12. The alkyl groups can be straight chained or branched chained in structure. Furthermore, if the phenol reactant is a polyalkylated phenol, the alkyl groups can be like groups or unlike groups. Non-limiting examples of the alkylphenol reactants are dibutylphenol, di-t-amylphenol, di-n-hexylphenol, amylpropylphenol, disecondary-amylphenol, t-octylphenol, triisopropylphenol, nonylphenol, decylphenol, and dodecylphenol.

The reaction between the alkylphenol reactant and P205 is usually carried out at temperatures of between about 75C. and about C. The time of reaction will vary from about one hour to about 15 hours, depending upon the particular reactants used. Examples of the preparation of the reaction products contemplated herein are set forth in the co-pending application of Otto et a1., Serial Number 143,156, filed February 8,

1950,"now' matured "into"U.S. Patent No. 2,638,447, issued-May-12, 1953 Itmusbbe'noted, however, that alkylphenol-PzOs reaction products having more than 12 carbon atoms in the alkyl groups in the alkylphenol are not utilizableherein. Thusreaction products-made-from 5 tetradecylphenoland from. wax zphenolfz. were found-v unsatisfactory for the purposes of the present invention.

The antifoamant compositions :of=.this.inventioruconsistof. the monoester'of sorbitol anhydrides.=and'an:alkyl phenol-PzOsreaction. product-,u asv defined-.hereinbefore. These-compositions must contain-betweenzabout 2 .per T centand about 30 per cent, :by-weight, of-the monoester; oft dehydrated sorbitoL. The;balance,-.-i. e., between about 98 per cent and about.70 percent, 'by weight, is the alkyl-+ phenoleP-zOs --reaction"pr oduct.:'. In other. wordsgthe-weight. ratio; of 1 the -rnonoester to the alk-ylphenol PzOs reaction product must fall within the. srange: ofrbetweenvzaboutc. 2:98, respectively, and about 30:70, respectively, i. e., between about 0.02 and about 0.43. Combinations having ratios outside.athesevlimitsi'are ineffective in the present invention.

The amount bf the aforedescribd combinations which is added to the lubricatingoil will vary between about 0.1 per cent and about 1.5 percent, by weight. Concentrations below 0.1 percent are .effectivewto some extent. However, substantially complete elimination of foaming tendencies is not achievedtat these. concentrations.

It must be strictly understood that the :non-foaming oil compositions of this invention can be :produced in two ways. By one method, the dehydrated sorbitol monoester and the alkylphenol-PzOa reaction product can be blended together in the aforedescribed ratios, and the resulting combination added to the mineral lubricating oil in the concentrations set forth hereinbefore. Alternatively, the monoesterand the--al k ylphenol-P2O5 reaction product can be added to the; oil individually, provided, however; thatntheguare ultimately present in the oil in the ratios. set forth hereinbefore, and that the combined concentration falls within the aforedescribed range. When added separately, the tmonoester: :of t sorbitol anhy- 4 dride is added to theoilrat.concentrationszbetween about 0.002 per cent'and about045'percent, 'by' weight. Simi-.. 1arly',;'the alkylphenol-PzO5.-reaction PIZOduCtzis added-to the oilat concentrationstof?between-about 0.0.7 pencent and'about 1.47 per cent, byyveight; It=is;very'important, however, when workingwithin'these. ranges,-.(1) that-thew ratio of ester to reaction product be maintained,-and'.(2). thattthe.combined-concentrations 'fallwithin-the range; set.- forth hereinbefore. Thus, .for; example, 0.002iweight, per: cent ofnsorbitol anhydridemono-oleatexaddedaito anioil containing 0.5 .weight percent 20f the-:di-t-amylphenob P205 'reactionzproduct is inefiectivez. Although the. con-.1 centrations of. the-additivesin this :blend. falliwithimthezt ranges specified, .itnwilLwbe notedcthat. thezratio. of: theft mono-'oleate to..the-. reaction-.i-product was -.on1y about 04:99.6, i. e., about'0.-004. I Since thecratiomustitfall within the range of between tabout=2 :98 and about .30 i. e.,.betweenzaboutiLOZ and about 0:43, ibwillibezap preciated that the :ratio-inthis caseyis outside :theeffective range.v

A- preferredembodiment of theipresentdnvention .is 2: non-foaming extremeapressure lubricating oil. Since-thew alkylphenolsPzos reaction. productsv impart extreme pressure characteristics. to lubricatingpilsi they are. frequently used .as at:1east-.one:.componentthereofw Howevenrin orderto. achieve-good.extreme pressure propertiesimam oil, the alkylphenol-PzOsreaction produ'ctshbuldrbe pres-F ent in somewhat largercamounts: 1113.11. 'S6it7tf0ttl11h1'6iH-i: before, namely, at concentrations; -of about;0:1.tper cent and 1.5 percent, byweighta Auprefe'rred:concentration: is about:0.'5 perwcentlv Accordinglygdn'ordenztta render? these extreme :pressure"v oils non+foaming,1 the. fsorhitol'i-an-z hydride rnonoester willbe added .at concentrationslofibe-s. tween aboutO.-002 .per=cent.- andabout .0545 :per centgbyr' weight; When'operating ewithin thesexrangegscthet'ratios. 79 defined "hereinbefore must -be rmaintained; The-'concen-rs tration of the anti foamant combination:presentsinzthese oil compositions willrlbe between about.0.1 .perncent and about. 2.5 per cent, by weight; An iimprovedoextremew pressure .rlubricating toil of .the ttypeicontemplate'd within 30 the-preferred embodiment IOfiithiSliIlYBIltiDl'lUiSLdiSClOSCd'E inrthe Otto. et.'al-;. co-pending application;Seriala'Numbem 143,156, filed-FebruaryS; 1950; now maturedtintod]: SI. Patent.No:.- 2,638,447, issued May a12,f195 3.3 Brieflyide scribed,:. these mineralilubi'icating oils conta'inafl) beetween about one per cent and about 10 per cent, by weight, of-a product-obtained by chemically substitutinga partonly of the chlorine in a chlorinated aliphatic material with a thiocarbonate group,- -(2) between about 0.1 per cent and about 3 per cent, by weight, of dihydroabietyl malate, and (3) betweenabout 0.1 per cent and about 1.5 per cent by weight ofan alkylphenol-PzOa reaction product. Reference should. be=made= to .this application for details of the compositions contemplated. These compositions-have excellent extremepressure properties. They 1 do, however, exhibit-atendecy totfoam; Suchcompositions are rendered non-foaming by the presentinvention. As disclosed in the Otto et al. application, the alkylphenolrcan have-a .totaLof 'lesse than eight and more than twelve carbon a:atoms:..inx-thez.alkyl groups for extreme pressure purposes. Thus, for example, a waxalkylated phenol=PfiO5react-ion product is-operable as an extreme pressure agent. In such a case, another alkylphenol-P205 reaction product withinwthe ranges, contemplated herein 'must be .added .with the .sorbitolanhydride monoester. to achieve .nonafoaming: ,characteristics.

Thcfictiveness. of .the .antifoarnant. compositions. 015.: this invention is not impaired by the presence .of "other additives..in .the lubricating. oil .blend. The. non-foaming oilljcompositions oftthislinvention. can -contain.-a. wide varietyof other oil. .additiomagents. for.,the..purpose .of improving -;othercharacteristics ofrthenoil Accordingly, extreme. pressure. addition agents, .antirust agents, oil-.: in'ess. agents, .pour point. depressants, .detergents,..and. .the. lil e,:v wellf known; to those-skilled inithe-art, can bev .added: to .,a .lubficatingpil along ,with, the antifo'amantcompositions of thisiinventiom- Oil. concentrates are also contemplated. herein; Thus,

blehdstcontaining. ,upwards'. oars jpencent as. much as. ab.out.49 .per. cent, .by fW6igl1f,.Of .the, antifoamant, compo-s. sitions. of. this 1 invention. ina. suitable lubricating oil .can

be. used..l. Thesev .concentratescan subsequently be diluted.

withla.base.oilIiin.ordentoachievean ultimate blend .co11-. tain'ingthe desired concentration of the. antifo'amantcomu position...

The following specific examples; are for.the..purpose..ofillustratingt the .antifoamant compositions of .fthisinVention. ItI rnusLbe .stric'tly' .unde'rstood that. this.-inventio'n isnot to .be limited .to Ih'easpecific fatty. acid monoesters of.sorbitol.janhydrides. and: .Ipolyoxyethylene derivatives thereof, and..'to the-.talkylphenol-Pa'osl reaction products...

disclosediherein,.or..to..the concentrationsused; As.will be apparent; to.-.those. skilled in .the. .art, .othermonoesters of sorbitol anhydridel and alkylphenol-PaOs reactionprod-U nets, and other concentrations thereof-can.be..used,j.asv has-been. fullydisclosed .hereinbefore:

The test ;procedu"re .,use.d .Zto determine. .the. foaming,

characteristics. oi the.-1ubr'icatin .9i1 is the. CRC-fifoam test: designation -.Li.14,.' which is? described .'in.-.the ',.CR'C I hand-T bookL. lnrbrief, thisitest, involves. ;blQ'wing, airi through. a

sampleof. the. oiLilndertest at.75"? F.for 5 minutes. The sample. is. .contained.11 1...a. graduatedfcylm'den. Atnthe'. end .of'the blowing perlod, the..vo1ume .oiifo'am is. noted.

The -volume of foam, at, the. end of a 10-minute..co1laps e 0 period,. as. wasscalled. for... m ..tl1c ..tes.t,-. is not treported herein... The. non-foaming ,oilslof this invention show virtuallylno foam at. the end of the blowing period,jthus. no

collapse. period is required.

The base oilused .'.to..1llustrate' the compositions of this].v

r invention is a 'solvent-refinedresidual oil." This oilhas an- A. P. I. gravity of about 27.5;a Sayb'oltfuniversal. viscositypf 1075 "at 100 F. and.90-95 at 212. F a pour point.

of +25 F5, and a fraction poiritof 460. F'.

In the. following examples commercially available,

Spans and..Tweens were used. Of-thematerials tested,'.

Span ,80 is defined as sorbitol anhydridexmono-oleate. Span. is isorbitol anhydride 'triole'ate. is polyoxyethylene' sorbitol. anhydridei mono-laurate. Tween 61 is polyoxyethylene sorbitolanhydride mono. stearate. Tween :81 'is' polyoxyethylene sorbitol Janhy; dride.mono-oleate. Otheridentifying;characteristics. of. these materials can be :obtained from the manufacturers' brochure identified hereinbefore.

Examples 1 througlgd Three. lubricating oihble'ndssweresubjected-to the foaming-retest. The FfifSt :zblend comprised 'raboutt-0t2' -pencent Tweena81t in the ftest oili Thelsecond blendzcomprisedther.

testzoil containing aboutz0;l per cent;Tween: 81-andaboutn 0.5 :perxcent ofrthe -.reaction productcfof :3 moles. of sdi-t-a. amylphenohwith 1 'mole tofiaphosphorus pentoxide.

Thea":

third blend comprised the base oil containing about 0.01 per cent Tween 81 and about 0.5 per cent of the amylphenol-Pzos reaction product. Pertinent data and test results therefor are set forth in the table.

Examples 5 through 8 Two portions ofthe base oil containing 0.5 per cent by weight of the reaction products of 3 moles of di-t-amylphenol with 1 mole of phosphorus pentoxide were blended with varying amounts of Tween 61 and Tween 21. Pertinent data on these blends and foam test results therefor are set forth in the table.

Example 4 An extreme pressure lubricating oil composition was prepared by blending in the base oil 5 per cent by weight of a chlorinated Xanthate produced by reacting chlorinated kerosene with sodium ethyl xanthate, 1 per cent by weight of di-hydroabietyl malate, 0.5 per cent by weight of the alkylphenol-PzOs reaction product of Examples 1 through 3, and 0.2 per cent by weight of Tween 81. This composi- 7 tion, when subjected to the foaming test, gave the results as set forth in the table.

Example 9 In the base oil were blended 0.2 per cent by weight of Span 80 and 0.5 per cent by weight of the alkylphenol- P205 reaction product of the preceding example. This blend, when subjected to the foam test, gave the results set forth in the table.

Example 10 Example 11 For purposes of comparison, a blend was prepared comprising 0.2 per cent by weight of Span 85 and 0.5 per cent by weight of the reaction product of 3 moles of octylphenol (mixed isomers) with 1 mole of phosphorus pentoxide in the base oil, as will be apparent from the data set forth in the table. This blend foamed appreciably in the foaming test.

It will be appreciated, from the foregoing examples, that combinations of sorbitol anhydride monoesters with certain alkylphenol-PzOs reaction products eliminate the foaming tendencies of mineral oils, when added thereto in definite amounts and in definite proportions. Likewise, standard gear oil formulations containing other E. P. additives are beneficiated in that respect. It is to be noted that the ester of the sorbitol anhydride must be a monoester and must contain between 12 and 18 carbon atoms in the acid radical.

Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope thereof, as those skilled in the art will readily understand. Such variations and modifications are considered to be Within the purview and scope of the appended clauns.

TABLE Cone of Wt. Exam- Foam Oomp.,Wt. A 1 B 2 Ratio, Percent A/B 3 Blank nil 400-000 None 470 diamylphenoL nlil nil nil nlI nil nll nil do nil Span 85- octylphenol. 170

1 A=Borbitol anhydride monoester or polyoxyethylene derivative. 1 B=A1ky1pheno1 reacted with P105 in a 3:1 molar proportion.

3 B=AlkylphenoI-Pa0s reaction product.

4 Plus chlorinated xauthate and 1% dlhydroabletyl malate.

What is claimed is:

1. A mineral lubricating oil containing between about 0.1 per cent and about 1.5 per cent, by weight, of an antifoamant composition consisting of between about 2 per cent and about 30 per cent, by weight, of an ester selected from the group consisting of aliphatic monoesters of sorbitol anhydrides and aliphatic monoesters of polyoxyethylene derivatives of sorbitol anhydrides, and between about 98 per cent and about 70 per cent, by weight, of the reaction product formed by reacting about 3 moles of an alkyl phenol having a total of between about 8 carbon atoms and about 12 carbon atoms in the alkyl radicals thereof, withabout 1 mole of phosphorus pentoxide, at a temperature of between about 75 C. and about C.

2. A mineral lubricating oil containing between about 0.1 per cent and about 1.5 per cent, by weight, of an antifoamant composition consisting of between about 2 per cent and about 30 per cent, by weight, of sorbitol anhydride mono-oleate and between about 98 per cent and about 70 per cent, by weight, of the reaction product formed by reacting about 3 moles of diamylphenol with about 1 mole of phosphorus pentoxide, at a temperature of between about 75 C. and about 125 C.

3. A mineral lubricating oil containing between about 0.1 per cent and about 1.5 per cent, by weight, of an antifoamant composition consisting of about 17 per cent, by weight, of sorbitol anhydride mono-oleate and about 83 per cent, by weight, of the reaction product formed by reacting about 3 moles of diamylphenol with about 1 mole of phosphorus pentoxide, at a. temperature of between about 75 C. and about 125 C.-

4. A mineral lubricating oil containing between about 0.1 per cent and about 1.5 per cent, by weight, of an antifoamant composition consisting of between about 2 per cent and about 30 per cent, by weight, of sorbitol anhydride mono-oleate and between about 98 per cent and about 70 per cent, by weight, of the reaction product formed by reacting about 3 moles of diamylphenol with about 1 mole of phosphorus pentoxide, at a temperature of between about 75 C. and about 125 C.

5. A mineral lubricating oil containing between about 0.1 per cent and about 1.5 per cent, by weight, of an antifoamant composition consisting of about 2 per cent, by weight, of sorbitol anhydride mono-oleate and about 98 per cent, by weight, of the reaction product formed by reacting about 3 moles of di-amylphenol with about 1 mole of phosphorus pentoxide, at a temperature of between about 75 C. and about 125 C.

6. A mineral lubricating oil containing between about 0.1 per cent and about 1.5 per cent, by weight, of an antifoamant composition consisting of between about 2 per cent and about 30 per cent, by weight, of sorbitol anhydride monolaurate and between about 98 per cent and about 70 per cent, by Weight, of the reaction product formed by reacting about 3 moles of di-amylphenol with about 1 mole of phosphorus pentoxide, at a temperature of between about 75 C. and about 125 C.

7. A mineral lubricating oil containing between about 0.1 per cent and about 1.5 per cent, by weight, of an antifoamant composition consisting of about 2 per cent, by weight, of sorbitol anhydride monolaurate and about 98 per cent, by weight, of the reaction product formed by reacting about 3 moles of di-amylphenol with about 1 mole of phosphorus pentoxide, at a temperature of between about 75 C. and about 125 C.

8. A mineral lubricating oil containing between about 0.1 per cent and about 1.5 per cent, by weight, of an antifoamant composition consisting of between about 2 per cent and about 30 per cent, by Weight, of polyoxyethylene sorbitol anhydride mono-oleate and between about 98 per cent and about 70 per cent, by weight, of the reaction products formed by reacting about 3 moles of di-arnylphenol with about 1 mole of phosphorus pentoxide, at a temperature of between about 75 C. and about 125 C.

9. A mineral lubricating oil containing between about 0.1 per cent and about 1.5 per cent, by weight, of an antifoamant composition consisting of about 29 per cent, by weight, of polyoxyethylene sorbitol anhydride monooleate and about 71 per cent, by weight, of the reaction product formed by reacting about 3 moles of di-amylphenol with about 1 mole of phosphorus pentoxide, at a temperature of between about 75 C. and about 125 C. 

1. A MINERAL LUBRICATING OIL CONTAINING BETWEEN ABOUT 0.1 PER CENT AND ABOUT 1.5 PER CENT, BY WEIGHT, OF AN ANTIFOAMANT COMPOSITION CONSISTING OF BETWEEN ABOUT 2 PER CENT AND ABOUT 30 PER CENT, BY WEIGHT, OF AN ESTER SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC MONOESTERS OF SORBITOL ANHYDRIDES AND ALIPHATIC MONOESTERS OF POLYOXYETHYLENE DERIVATIVES OF SORBITOL ANHYDRIDES, AND BETWEEN ABOUT 98 PER CENT AND ABOUT 70 PER CENT, BY WEIGHT, OF THE REACTION PRODUCT FORMED BY REACTING ABOUT 3 MOLES OF AN ALKYL PHENOL HAVING A TOTAL OF BETWEEN ABOUT 8 CARBON ATOMS AND ABOUT 12 CARBON ATOMS IN THE ALKYL RADICALS THEREOF, WITH ABOUT 1 MOLE OF PHOSPHORUS PENTOXIDE, AT A TEMPERATURE OF BETWEEN ABOUT 75* C. AND 125* F. 